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Outdoor Heat Pump Runs after inside unit turns off

Hi All,

Heat Pump -
Outdoor Rudd ~13 yrs
Indoor Rheem ~2 yrs

I noticed a few weeks ago that my indoor coils were icing up/frosting over. I called a tech who noticed that I had too many vents closed and also cleaned my outdoor coils. I also replaced with a new filter. My house both before and after would cool very well except when frosted. I also informed the tech that it seemed like there was still liquid flowing when the inside unit was off. He responded that this may just be normal cycling. This only seemed to happen when the indoor coils were frosted. Tech also checked all contacts and temps and said the unit is in perfect working order. Fast forward a week and no real change. Tech returned with no idea of the problem and decided to try increasing the speed of the indoor blower. This worked fine for a few days. Fast forward a week and then I noticed that the outdoor unit would not turn off and the only way I could get it off was to use the breaker. Tech came and fixed the contactor which was burnt. Unfortunately this still didn't fix the original problem but got it working again. As this story continues I've been paying more attention and I have noticed that there are times when the thermostat will click on and both the indoor and outdoor unit turn on and blow nice cold air. The indoor unit will turn off/stop blowing when the temperature is reached but the outside unit continues to run and will eventually turn off. I timed it once and it was about 45 minutes. The outdoor unit will turn off if I use the thermostat. The two units sometimes work in sync and sometimes the outdoor unit stays on. This then leads to the indoor coils frosting up.

I've searched online with no ideas and am reluctant to call the same company back but would hate to call another person if this is truly not a hard problem to solve. Welcome any thoughts or ideas. I'm handy and can use a voltmeter if needed. Other info that may or may not be of interest I purchased and installed a new programmable thermostat about a year ago.

The big question to ask the installer, how does he know the right size piston for the Ruud heat pump is installed in the Carrier air handler? I'd think the best solution with this mismatched setup of efficiency and brand is having an R22 expansion valve installed.

I am in agreement with socotech, I would be looking at the reason why there is low voltage to the contacter. You need to tell the technician about the condensing unit running after the indoor unit has shut off, so they can focus on the low voltage connections.